diff --git a/internal/errutil/error_test.go b/internal/errutil/error_test.go
new file mode 100644
index 0000000..5c1784e
--- /dev/null
+++ b/internal/errutil/error_test.go
@@ -0,0 +1,22 @@
+package errutil
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCephError(t *testing.T) {
+	radosErr := cephErrno(107)
+	assert.Equal(t, "Transport endpoint is not connected", radosErr.Error())
+
+	cephFSErr := GetError("cephfs", 2)
+	assert.Equal(t, "cephfs: ret=2, No such file or directory",
+		cephFSErr.Error())
+	assert.Equal(t, 2, cephFSErr.(cephError).ErrorCode())
+
+	rbdErr := GetError("rbd", 2)
+	assert.True(t, errors.Is(cephFSErr, rbdErr))
+	assert.True(t, errors.Unwrap(cephFSErr) == errors.Unwrap(rbdErr))
+}